Determination of factors that effect the formation of sludge granules on UASB reactors

In this study, determination of factors that effect on formation of granulation was searched in upflow sludge blanket (UASB) reactors. Effects of FeCl2.4H2O and FeCl3.6H2O addition formation and improvement of granulation was analysed. Cheese whey and beet molasses were used as substrate. Cheese whey taken from the AOÇ cheese producing industries has 70000 mgCOD/L organic load initially. Beet molasses taken from the Ankara Şeker Fabrikası A.Ş. (Ankara Sugar Industry) has 4550 mgCOD/L organic load in 10 g/L molasses solution. Two UASB reactors that parallel operated with each other and has 3.4 liters volume (R1 and R2) were used in cheese whey study. One reactor (R) which has same volume was used in beet molasses study. Reactors were inoculated with the anaerobic activated sludge taken from ASKİ Wastewater Treatment İndustry. Cheese whey and beet molasses were feed to the UASB reactors at a rate of 0.56 mL/min. All reactors were operated at a hydraulic retention time of 4 days at applied organic loading rates. For cheese whey study, inital sludge height was 1.8 cm for R1 and 2.6 cm for R2. Granule formation and effects of FeCl3.6H2O on enhancement of granulation by using 1/10 dilution of cheese whey were observed. Also cheese whey was diluted by the ratios of 1/20, 1/10, 1/5, 174, 1/3 and 1/2, respectively. These mixtures were used as the fed solution for analysing of formation and enhanced granulation in this diluting rate. Granules accessed to sensible size in UASB reactors at 33th day. Granule sizes that accessed to 2 mm were observed at 44th day. After 50 day, the height of bed was observed as 6.5 cm for R1 and 8.0 cm for R2 with COD removal efficiencies of 38.51% and 38.22% for R1 and R2, respectively. As of 73th day 0.012 g/L FeCl3.6H2O was added to substrate. In the end of 82nd day granule size in reactors was observed to access ~ 5-6 mm. Consequently, the heighest of sludge bed was get at 1/2 diluting rate and effect by FeCl3.6H2O. So, in the end of 82nd day bed heightes measured as R1 27.50 cm and R2 26.00 cm. For molasses study of first, initially reactor has 6.50 cm heigh of sludge bed. Beet molasses has organic load 4550 mgCOD/L in 10 g/L concentration. FeCl2.4H2O was added 0.35 g/L to substrat, was analyesed effects on granule formation. 19th day the heighest COD removal efficience was calculated as % 83.39. The heighest methane content % 28.34 was get at 9th day. Small granule parts that grown and has size 1-1.5 mm was observed at 26th day in the 1.5 cm part of the heigest sludge bed. By reason of pH decreasing relaized in reactor, occured granule stractures was observed dissapearing at 33th day. For molasses study of second, until 51th day wasn?t get COD removal. At 50th day Tween-80 was added to substrat for increasing excrete ECP by microorganisms. Until 57th day COD removal as 27.76 mgCOD/L was obtained at 56th day by Tween-80 addition.